1t5e
The structure of MexA
Structural highlights
FunctionMEXA_PSEAE The periplasmic linker component of the MexAB-OprM efflux system that confers multidrug resistance. Also functions as the major efflux pump for n-hexane and p-xylene efflux. Over-expression of the pump increases antibiotic and solvent efflux capacities. Required for assembly of the MexA/MexB/OprM complex. Implicated in the secretion of the siderophore pyoverdine.[1] [2] [3] The ability to export antibiotics and solvents is dramatically decreased in the presence of the proton conductor carbonyl cyanide m-chlorophenylhydrazone (CCCP), showing that an energized inner membrane is required for efflux. It is thought that the MexB subunit is a proton antiporter.[4] [5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMultidrug resistance among Gram-negative bacteria is conferred by three-component membrane pumps that expel diverse antibiotics from the cell. These efflux pumps consist of an inner membrane transporter such as the AcrB proton antiporter, an outer membrane exit duct of the TolC family, and a periplasmic protein known as the adaptor. We present the x-ray structure of the MexA adaptor from the human pathogen Pseudomonas aeruginosa. The elongated molecule contains three linearly arranged subdomains; a 47-A-long alpha-helical hairpin, a lipoyl domain, and a six-stranded beta-barrel. In the crystal, hairpins of neighboring MexA monomers pack side-by-side to form twisted arcs. We discuss the implications of the packing of molecules within the crystal. On the basis of the structure and packing, we suggest a model for the key periplasmic interaction between the outer membrane channel and the adaptor protein in the assembled drug efflux pump. Structure of the periplasmic component of a bacterial drug efflux pump.,Higgins MK, Bokma E, Koronakis E, Hughes C, Koronakis V Proc Natl Acad Sci U S A. 2004 Jul 6;101(27):9994-9. Epub 2004 Jun 28. PMID:15226509[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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